Tool for crimping electrical connectors



June 19, 1962 R. G. STUART-PRINCE 3,

TOOL FOR CRIMPING ELECTRICAL CONNECTORS 3 Sheets-Sheet 1 Filed April 27, 1959 INVENTOR.

RICHARD 6. STUART-PRINCE BY M Wv June 19, 1962 R. G. STUART-PRINCE 3, 3

TOOL FOR CRIMPING ELECTRICAL CONNECTORS 5 Sheets-Sheet 2 Filed April 27, 1959 lNVENTOR. RICHARD G. STUART-PRINCE June 19, 1962 R. G. STUART-PRINCE 3,039,337

TOOL FOR CRIMPING ELECTRICAL CONNECTORS Filed April 27, 1959 3 Sheets-Sheet 5 INVENT OR. RICHARD Q STUART-PNNCE M Wv L United States Patent 3,039,337 TOOL FOR CRIMPING ELECTRICAL CONNECTORS Richard G. Stuart-Prince, Camp Hill, Pa., assignor to AMP Incorporated, Harrisburg, Pa. Filed Apr. 27, 1959, Ser. No. 809,107 3 Claims. (CI. 81-15) A commonly used type of hand tool for crimping electrical connectors to wires includes a pair of crimping dies with a mechanism for closing the dies. In the use of such a tool, the ferrule of a connector is positioned to embrace the wire and this assembly is brought into position with the ferrule between the crimping dies. A closing force applied manually to the mechanism causes the dies to engage and compress the ferrule into secure engagement with the wire. Such crimping is a precision operation in which both the dies and the connector units to be crimped therein are held to very close tolerances. Unless the jaws are closed together to an accurately predetermined position, the advantage of such precision is lost and the connection between the connector and the wire may be less secure and electrically less perfect than is required. This can result either in rejection of the work on inspection or failure in use.

My principal object was to provide a tool which has means for preventing release or reopening of the dies until the connector has been fully crimped to the wire. Other objects will be apparent to those skilled in the art from a consideration of what follows A tool in accordance with my invention has stops on the dies limiting the closing of the dies to a precisely determined crimping relation, and a ratchet device consisting of a pawl and ratchet mounted in, or forming part of, the mechanism, the pawl operatively engaging the ratchet during the final closing of the dies, and automatically disengaging from the ratchet with yielding movement in the mechanism beyond the point at which the stops abut and crimping is completed, the pawl, upon disengagement from the ratchet, remaining out of operative engagement with it during opening movement of the dies. Such a tool differs from that shown in Carlsons Patent No. 2,618,993 in that Carlsons tool has a ratchet device which operates on both the closing and the opening movement of the dies; once the closing movement has been started it must be completed (as is the case with the present invention) and once the opening movement has been started it must be completed (in the present invention the opening movement can be interrupted at any stage and the closing movement started). The tool of this invention also differs from that of Dibners Patent No. 2,737,070. Dibners tool includes a ratchet which operates only on the closing movement of the dies but there is no teaching applicable to precision tools and no disclosure of stops o-r yielding movement in the mechanism beyond the point at which the stops abut.

I prefer that the tool has means to ensure that after crimping of a connector the pawl is again in operative engagement with the ratchet when the dies are next closed on an uncrimped connector; such a means ensures that the pawl is in operative engagement with the ratchet for each crimping operation to be performed with the dies. This means may take various forms, as may the tool itself. The means may, for example, ensure that the pawl operatively re-engages the ratchet if the dies are closed at any stage during the opening movement by a reversal of the direction of engagement of the pawl with the ratchet, or the means may obstruct the space between the dies to prevent removal of a crimped connector or positioning of an uncrimped connector until the pawl is again in a position to engage the ratchet operatively when the stops next abut.

By way of example two embodiments of the invention will be described with reference to the accompanying drawings. It should be understood that these embodiments are exemplary and not exhaustive or limiting.

In the drawings:

FIGURE 1 is a side elevation, with parts broken away, of one tool embodying the present invention;

FIGURE 2 is an exploded perspective view of certain parts of the tool shown in FIGURE 1;

FIGURE 3 is a view similar to FIGURE 1 showing the tool in a different position;

FIGURE 4 is a perspective view of the head of the tool shown in FIGURES 1 to 3 with a crimped connector in position between the dies of the tool;

FIGURE 5 is a perspective view of a part of a second tool embodying the present invention, certain parts being broken away for clarity;

FIGURES 6 and 7 are longitudinal sections of the ratchet mechanism shown in FIGURE 5 with the parts in different positions to show the operation of the mechanism; and

FIGURE 8 is a detail of the ratchet mechanism shown in FIGURES 5 to 7 showing the mounting of the ratchet mechanism.

The tool shown in FIGURES 1 to 4 comprises a pair of crimping dies 2 and 4 formed in a pair of jaws 6 and 8. Faces 10 and 12 of the jaws 6 and 8 form stops limiting the closing of the dies to a precisely determined crimping relation. The jaws 6' and 8 are pivoted between a pair of links, of which only one 14, can be seen in the drawings. The jaws 6 and 8 are in turn pivoted to handles 16 and 18 respectively, the handles themselves being pivoted together by a pin 20.

Mounted between the handles 16 and 18 is a ratchet device comprising a pawl 22 and a ratchet 2/4. The ratchet is pivoted to the handle 18 by a pin 26 and carries ratchet teeth 28. The pawl 22 is mounted in a pawl carrier 30 and pivots about a pin 32, being urged into the position shown in FIGURE 1 by a spring 34. The pawl carrier30 is pivoted to the handle 16 by a pin 36. The ratchet 2-4 can telescope with the pawl carrier 30.

Also pivoted to the pin 20 is a shutter 38 and a strap 40. Both the shutter and the strap are freely and independently rotatable on the pin 20. The shutter 38 lies between the jaw -8 and the link 14 and is cut out at 42 to permit movement relative tov the pin pivoting the jaw 8 to the link ,14. The shutter also has a cutout 44 which, when the shutter is closed as shown in FIGURE 4, partially obstructs the space between the dies. A spring 46 is held under compression between a lug 48 on the lower end of the shutter and a shoulder 50 formed in the strap 40; the strip has an extension 52. Mounted on the ratchet 24 are twofingers 54 and 5,6 which can engage the strap 40 or its extension 52. The shutter 38 is spring-biased either into the position shown in FIGURE 1, in which it does not obstruct the space between the dies, or into the position shown in FIGURE 3, in which it does obstruct the space.

The position of the parts of the tool shown in FIGURE 3 is that assumed by them at the, stage just before the handles 16 and 18 and therefore the dies 2 and 4v reach the fully open position; The pawl 22 is out of operative engagement with the ratchet teeth 28 of the ratchet 24 because the curved surface of the pawl rides over the crests of the teeth 28 and the nose of the pawl cannot engage the teeth. At the stage shown in FIGURE 3 a connector which has been crimped between the dies 2 and 4 cannot be removed from between the dies because the shutter 68 prevents'this (see FIGURE 4). Still referring to FIGURE 3 the finger 54 has just moved into contact with the extension 52 of the strap 50 and as the handles move from the position shown in FIGURE 3 to that shown in FIGURE 1 two actions take place. First,

the pawl 22 rides off the end of the ratchet teeth 28. Second, the finger 54 pushes the extension 52 to the right as seen in the drawings; the compression spring 46 is further compressed until the shutter and strap are aligned, at which point the strap 56 snaps to the right as seen in the drawings. At the same time the lug 48 on the shutter 38 is pushed to the left, so that the shutter itself moves away from the dies 2 and 4 thus permitting the removal of a crimped connector from between them. The action of the shutter and strap is similar to that of a snap-action electric switch.

In the fully open position, which is shown in FIGURE 1, the strap 46 is in contact with the finger 56 and as the handles are closed together to close the dies 2 and 4 on a fresh connector inserted between them the finger 56 will start pushing the strap 40 to the left. A connector can be freely inserted because the shutter is not obstructing the space between the dies at this moment. This pushing movement continues until the strap 40 is in line with the shoulder 38 at which point the strap 40 snaps to the left, and the shutter and related parts assume the position shown in FIGURE '3. This means that a connector is effectively locked in position between the dies.

During this closing movement of the handles and dies the nose of the pawl 22 engages the ratchet teeth 28 making it impossible to open the handles until such time as a complete crimping stroke has been made and the pawl 22 has disengaged from the ratchet by falling into the recess 25 under action of the spring 34. It is arranged that the faces 10 and 12 abut while the nose of the pawl is engaged in the valley between the last two teeth 28. The pawl is disengaged from the ratchet by further manual squeezing together of the handles to cause yielding movement of the mechanism. This yielding movement can be the result of flexing of the handles (which are conveniently made of bent-up sheet metal) or movement in the pivots of the mechanism. I

Accordingly, the ratchet device comprised of the ratchet 24 and the pawl 22 ensures that once a closing movement of the handles 16 and 18 and therefore of the dies 2 and 4 is started the movement must be completed. The shutter 38 ensures that a connector which has been crimped during the closing movement of the handles cannot be removed from between the dies, or an uncrimped connector cannot be inserted between them, until the ,dies are fully opened and the pawl 22 is again in a position to engage the ratchet 24 on a subsequent closing movement of the handles.

In the tool shown in FIGURES to 8, the head of the tool, comprising the jaws, dies and so forth, is not illustrated as it takes the same form as the head of the tool shown in FIGURES 1 to 4. A pair of handles 62 and 64 is pivoted by a pin (not shown) similar to the pin 20 of FIGURES l to 4. Mounted between the two handles, which are shown in the fully opened position, by two pins 66 and 68 is a ratchet device. The device consists essentially of a ratchet bar 70 and a pawl 72, the bar 70 being mounted to slide relative to the pawl 72 as thehandles, 62 and 64 are opened and closed. The ratchet bar 70 slides in a pawl carrier 74 through which the mounting pin 66 passes. The pawl 72 is mounted on a pin 80 and is biased into a position in which it is normally at right angles to the bar 70 by a spring 82; when in inoperative engagement with the bar 70 the pawl makes an angle of 45 with it.

The ratchet bar 70 is, made up of a pair of outer plates 86 and 88 and a central plate 90 having ratchet teeth 92. The central plate 90 has a limited degree of movement between the two outer plates 86 and 88 by virtue of a pair of slots 94 in the plate 96 at an angle of 45 to the length of the plate and a pair of pins 96holding the plates 86 and 88 apart and passing through the slots 94. The plate 96 'is urged into a position in which the teeth 92 project above the edgesof the plates 86 and 83 by a spring :7 ratchet mechanism is conventional.

4 98 mounted in a slot in the bottom of the plate 90 (see FIGURES 6 and 7).

FIGURE 8 shows the manner in which the bar is mounted to the handle 64. The pin 68 passes through a stud 100 which itself passes through holes in the plates 86 and 88. Between the plates the stud 100 has six flats similar to a nut and is prevented from rotating relative to the plates 86 and 88 by a pair of tabs 102. As the hole in the stud 100 through which the pin 68 passes is olfcentre of the stud, it is possible, by rotating the stud 100 before it is locked in position by turning in the tabs 102, to vary the distance between the pins 66 and 68 at the moment when the pawl 72 disengages from the last tooth 92 of the ratchet. This disengagement should take place when the stops on the dies, limiting their closing to a precisely determined relation, are abuting; to take account of manufacturing tolerances and so forth it is desirable to incorporate some simple adjustment in the mounting and the stud 100 provides this.

The tool shown in FIGURES 5 to 8 operates in the following manner; if the handles are fully open as seen in FIGURE 5 it is clear that when the handles are closed the ratchet bar 70 will start to move relative to the pawl 72. Once the pawl 72 is engaging one of the teeth 92 it will not be possible to open the handles again until the pawl 72 has travelled across all the teeth 92 and fallen down off the last tooth into a recess 104 and assumed its normal position. If at any stage in the passage of the pawl 72 over the teeth 92 an attempt is made to open the handles the pawl becomes jammed between the pin and the valley betwen two adjacent teeth. By use of the adjustment means shown in FIGURE 8 it is arranged that the pawl 72 is engaging the last of teeth 92 when the stops on the dies abut; release of the pawl from the ratchet is then accomplished by continuing application of the closing force to the handles 62 and 64- so that there is yieldingly movement between pawl and ratchet. While the pawl is riding over the teeth on the closing movement either the angular position of the pawl 72 or the height of the plate relative to the base of the housing 74 changes as the pawl moves from tooth to tooth; the relative strengths of the springs 98 and 82 determine which takes place.

During the closing of the handles the operation of the Once the closing stroke has been completed and the handles begin to be opened, the angular position of the pawl '72 with relation to the plate 90 alters and is positioned in the opposite sense. Specifically, during closing of the handles the pawl points to the left as shown in FIGURE 7; when opening, the pawl points to the right. Now, if the ratchet bar 70 were of a unitary construction, that is to say if the plates 86 and 88 and 90 formed a solid unit, and the opening of the handles were arrested at any stage before the pawl 72 had reached the last tooth 92 and fallen off the end of the bar (as shown in FIGURE 5) and a closing forcewas applied to the handles the tendency would be for the pawl to slip over the teeth without engaging them operatively. However, as the plate 90 can move away from the pawl 72 along a path defined by the slots 94, at a change from an opening movement to a closing movement the pawl 72 presses the plate 90 down against the action of the spring 98 (see FIGURE 6) and continued closing movement causes the ratchet mechanism to take up the position shown in FIGURE 7; it is not then possible to open the handles until the handles and the dies have been fully closed and the stops abut.

Accordingly, the ratchet. mechanism is such that once a closing movement of the handles is started, they cannot be opened until a complete stroke has been made. Then, if at any point on the opening stroke of the handles the opening movement is turned into a closing movement the pawl reverses its direction relative to the ratchet and again operatively engages the ratchet teeth, so that the closing 7 stroke must against be completed.

Changes in construction will occur to those skilled in the art and various apparently difierent modifications and embodiments may be made without departing from the scope of the invention. The matter set forth in the foregoing description and accompanying drawings is offered by way of illustration only. The actual scope of the invention is intended to be defined in the following claims when viewed in their proper perspective against the prior art.

I claim:

1. A tool for crimping an electrical connector onto a conductor wire comprising a pair of crimping dies, a mechanism for closing the dies, a ratchet device connected in the mechanism and including a ratchet and a pawl pivotal between a first and a second position, means for reversing the pawl position at the ends of the die moving stroke of said mechanism, the pawl being pivoted to said first position at the die-opened end of the stroke of said mechanism and being positioned to engage said ratchet to compel complete die closure upon die closure movement of said mechanism, the pawl in the second position being inclined relative to the ratchet to release said mechanism for reverse movement in a die-opening stroke, mounting means coupling the pawl and ratchet for motion toward and away from each other with a spring bias toward each other, said motion being independent of movement of said mechanism, said mounting means including means moving the pawl when in said first position into binding engagement with the ratchet on die-opening movement of said mechanism and moving the ratchet and paw] away from each other when the pawl is in Said second position to pivot the pawl from the second to the first position on a die closing stroke of the mechanism.

2. A tool for crimping an electrical connector onto a conductor wire comprising a pair of crimping dies, a mechanism for closing the dies, a ratchet device connected in the mechanism and including a ratchet and a pawl pivotal between a first and a second position, the pawl being in said first position in the die closure movement of said mechanism and engaging said ratchet to compel complete die closure, the pawl in the second position permitting movement of said mechanism to open the dies, means for reversing the pawl position at the ends of the die moving stroke of said mechanism, mounting means coupling the pawl and ratchet for motion toward and away from each other with a spring bias toward each other, said motion being independent of movement of said mechanism, said mounting means including means constraining said motion along a line in substantially the same direction as the inclination the pawl assumes in said second position so that the pawl engages and drives away the ratchet and pivots to said first position on die-closing movement of said mechanism.

3. A tool for crimping an electrical connector onto an electrical conductor comprising a pair of crimping dies, a mechanism for closing the dies, stops on the dies limiting the closing of the dies to a precisely determined crimping relation, and a ratchet device connected in the mechanism and including a pawl and a ratchet, the pawl operatively engaging the ratchet during the final closing of the dies, and automatically disengaging from the ratchet with yielding movement in the mechanism beyond the point at which the stops abut and the crimping is completed, the pawl, upon disengagement from the ratchet, remaining out of operative engagement with it to permit opening movement of the dies, the pawl re-engaging the ratchet operatively to compel closure of the dies upon reverse movement of the mechanism in a direction to close the dies, the ratchet and pawl being capable of movement toward and away from each other and biased toward each other by a spring, the pawl reversing its direction of engagement with the ratchet upon disengagement from the ratchet and again reversing its direction of engagement with the ratchet upon movement of the mechanism to close the dies, by virtue of relative movement of the pawl andratchet away from each other against the action of the spring, said ratchet comprising a first member connected in the mechanism and a second member carrying the ratchet teeth, the two members being connected together face-to-face by a pin in the first member riding in a slot in the second member, the slot being inclined in the same direction as that adopted by the pawl during opening movement, said second member being biased towards the pawl by said spring.

References Cited in the file of this patent UNITED STATES PATENTS 2,440,040 Burton Apr. 20, 1948 2,618,993 Carlson Nov. 25, 1952 2,737,071 Dibner Mar. 6, 1956 FOREIGN PATENTS 608,213 G y -r--, 

